Effects of menopausal hormone therapy on cardiovascular diseases and type 2 diabetes in middle-aged postmenopausal women: analysis of the Korea National Health Insurance Service Database

Menopausal Hormone Therapy in Women with Type 2 Diabetes Mellitus: An Updated Review

Menopause is accompanied by several metabolic adaptations, which are related to insulin resistance, increased total body fat mass, and central abdominal fat accumulation, predisposing women to type 2 diabetes mellitus (T2DM) development. Metabolic syndrome has a high prevalence in postmenopausal women, indicating the loss of estrogen protection on metabolic and cardiovascular health. Moreover, earlier age at menopause has been related to increased risk of T2DM. Menopausal hormone therapy (MHT) has favorable results in glucose metabolism. Indeed, it reduces the risk of T2DM in women without this condition and improves glycemic control in women with T2DM. Before MHT initiation in women with clinical indications, it is imperative to assess their cardiovascular disease (CVD) risk, using official electronic algorithms for score calculation. The latter will determine regimen, dose, and administration route of MHT. Oral estrogens are preferable in women with low CVD risk, while transdermal administration is indicated in those with moderate and high CVD risk, as the risk of stroke and venous thromboembolism (VTE) is increased with oral administration. Oral 17β-estradiol is usually preferred in women with T2DM, as this route has more beneficial effects on glucose metabolism. Oral estrogens are also suggested in perimenopausal or recently postmenopausal women with low CVD risk. Although oral estrogens have favorable effects when indicated, the risk of VTE or stroke should always be considered. Micronized progesterone, dydrogesterone, and transdermal norethisterone are the progestogens used in postmenopausal women with T2DM and intact uterus. MHT should not be initiated in women > 60 years or > 10 years in menopause, as there is an increased thromboembolic risk in women with established atherosclerosis and no additional cardiovascular benefit in women without atherosclerosis. In conclusion, MHT administration in postmenopausal women with T2DM can be safe and effective as long as the therapeutic regimen has been properly selected according to their cardiovascular, metabolic, and fracture risk.

Comparison of Operational Definition of Type 2 Diabetes Mellitus Based on Data from Korean National Health Insurance Service and Korea National Health and Nutrition Examination Survey

BACKGROUND

We evaluated the validity and reliability of the operational definition of type 2 diabetes mellitus (T2DM) based on the Korean National Health Insurance Service (NHIS) database.

METHODS

Adult subjects (≥40 years old) included in the Korea National Health and Nutrition Examination Survey (KNHANES) from 2008 to 2017 were merged with those from the NHIS health check-up database, producing a cross-sectional dataset. We evaluated the sensitivity, specificity, accuracy, and agreement of the NHIS criteria for defining T2DM by comparing them with the KNHANES criteria as a standard reference.

RESULTS

In the study population (n=13,006), two algorithms were devised to determine from the NHIS dataset whether the diagnostic claim codes for T2DM were accompanied by prescription codes for anti-diabetic drugs (algorithm 1) or not (algorithm 2). Using these algorithms, the prevalence of T2DM was 14.9% (n=1,942; algorithm 1) and 20.8% (n=2,707; algorithm 2). Good reliability in defining T2DM was observed for both algorithms (Kappa index, 0.73 [algorithm 1], 0.63 [algorithm 2]). However, the accuracy (0.93 vs. 0.89) and specificity (0.96 vs. 0.90) tended to be higher for algorithm 1 than for algorithm 2. The validity (accuracy, ranging from 0.91 to 0.95) and reliability (Kappa index, ranging from 0.68 to 0.78) of defining T2DM by NHIS criteria were independent of age, sex, socioeconomic status, and accompanied hypertension or dyslipidemia.

CONCLUSION

The operational definition of T2DM based on population-based NHIS claims data, including diagnostic codes and prescription codes, could be a valid tool to identify individuals with T2DM in the Korean population.

Association of menopausal hormone therapy with gastric and colorectal cancer risks in Korean women: A nationwide population-based cohort study

BACKGROUND

Menopausal hormone therapy (MHT) has been associated with a decreased risk of gastric cancer (GC) and colorectal cancer (CRC); however, few studies have been conducted in diverse ethnic groups, particularly in the Asian population. Therefore, the current study evaluated if MHT is inversely associated with GC and CRC in East Asia using a representative population-based study in Korea.

METHODS

This retrospective cohort study was conducted using the National Health Insurance Service-National Sample Cohort 2.0 in South Korea from 2002 to 2015. A total of 196,095 women aged ≥40 years were included in the study. The numbers of participants who did and did not use MHT were 19,063 (9.7 %) and 177,032 (90.3 %), respectively. Hazard ratios (HRs) and the corresponding 95 % confidence intervals (CIs) were estimated using a time-dependent Cox proportional hazards model. Age was considered as a time scale, and other confounding factors, including income levels based on insurance premiums, region of residence, and comorbidities, were included in the multivariable-adjusted model.

RESULTS

The total number of incident cases of GC and CRC were 1339 (0.68 %) and 1428 (0.73 %), respectively. We observed an inverse association of the use of estrogen replacement therapy (ERT; estrogen-containing therapy regardless of other regimen types) with GC [HR (95 % CI):0.68 (0.51-0.90)], CRC [0.57 (0.42-0.78)] and gastrointestinal cancer [GI, 0.63 (0.51-0.77)]. In the analyses by CRC subsite, the risks of both colon and rectal cancers were associated with ERT. In addition, both estrogen and combined estrogen and progestogen regimens were significantly associated with CRC and GI cancer.

CONCLUSION

ERT was associated with a decreased risk of GC and CRC. Our findings support the protective effect of estrogen against GC and CRC in Korean women.

The interplay between diabetes mellitus and menopause: clinical implications

The menopausal transition is an impactful period in women's lives, when the risk of cardiovascular disease is accelerated. Similarly, diabetes mellitus profoundly impacts cardiovascular risk. However, the interplay between menopause and diabetes mellitus has not been adequately studied. The menopausal transition is accompanied by metabolic changes that predispose to diabetes mellitus, particularly type 2 diabetes mellitus (T2DM), as menopause results in increased risk of upper body adipose tissue accumulation and increased incidence of insulin resistance. Equally, diabetes mellitus can affect ovarian ageing, potentially causing women with type 1 diabetes mellitus and early-onset T2DM to experience menopause earlier than women without diabetes mellitus. Earlier age at menopause has been associated with a higher risk of T2DM later in life. Menopausal hormone therapy can reduce the risk of T2DM and improve glycaemic control in women with pre-existing diabetes mellitus; however, there is not enough evidence to support the administration of menopausal hormone therapy for diabetes mellitus prevention or control. This Review critically appraises studies published within the past few years on the interaction between diabetes mellitus and menopause and addresses all clinically relevant issues, such as the effect of menopause on the development of T2DM, and the management of both menopause and diabetes mellitus.